1. Field of the Invention
The invention relates generally to the field of audio processing, and more particularly, to an audio processing apparatus in a communication system with a microphone array.
2. Description of the Related Art
In a communication system, there are three components that are picked up by a microphone, they include: a source signal, interference and echo. The source signal is a desired signal, such as a voice of a speaker. Additionally, only the source signal is required to be sent to a far end side. Thus, echo and interference are considered to be the most objectionable artifacts occurring in communication systems. The echo can be a result of a mismatch at the hybrid network, such as in the network echo case, or the reflections caused by a reverberant environment, such as an acoustic echo. An echo can manifest from the originator in a speech signal, wherein the originator is able to hear his/her own speech after a certain delay. With either kinds of echo, an annoyance factor increases as the amount of the delay increases.
Meanwhile, interference, such as environment noise, also disrupts the proper operation of various subsystems of a communications system, such as the codec. Different kinds of environment noise can vary widely in their characteristics, and a practical noise reduction scheme has to be capable of handling noises with different characteristics.
In order to properly remove the interference and echo picked up by the microphone (or microphone array), an adaptive beamforming filter and adaptive echo cancellation filter are respectively adopted in communications systems. However, as the echo and interference increases, filtering performance thereof degrades. Thus, a novel audio processing method and apparatus in a communication system with a microphone array are proposed.